Abstract

Thrips, Thrips tabaci Lind. (Thysanoptera: Thripidae), is a key pest of garlic in Brazil. This study aimed to evaluate the influence of spacing on T. tabaci infestation of a garlic crop. The experiment was conducted at the experimental farm of the Goiano Federal Institute (Instituto Federal Goiano – IF Goiano) - Campus Urutaí. The experimental design was a randomized block with nine treatments and spacing in single rows (0.20 × 0.10 m, 0.25 × 0.10 m and 0.30 × 0.10 m) and double rows (0.20 × 0.10 × 0.10 m; 0.20 × 0.15 × 0.08 m; 0.25 × 0.10 × 0.10 m; 0.25 × 0.15 × 0.08 m; 0.30 × 0.10 × 0.10 m; and 0.30 × 0.15 × 0.08 m). The Chonan 15 genotype was used in three replicates. At 30, 50 and 70 days after emergence (DAE), evaluations on the following features were carried out: leaf length, number of leaves, angle between the two central leaves, damage and number of thrips per plant. At the end of the crop cycle, the plants were harvested. Individual cured bulb mass, estimated commercial yield, number of cloves per bulb and bulb diameter were also evaluated. Spacing influenced the angle between the central leaves, with spacing of 0.30 × 0.15 × 0.08 m, among the least dense spacing, producing the widest angle (26.96^o), suffered one of the highest degrees of insect damage. A spacing of 0.25 × 0.10 m had the highest number of thrips per plant (2.99). Spacing influenced production, with the highest yield occurring with a spacing of 0.25 × 0.15 × 0.08 and 0.30 × 0.10 × 0.10 m (14.37 and 13.51 t/ha, respectively). The least dense spacing produced the largest bulb diameter (42.80 mm) and mass (30.66 g).

Key words: Allium sativum, insect, Thrips, plant architecture, non preference.